Problem with 16bit-ADC MAX11060

[SerialCreators]

Hi

I am using MAX11060 as a adc for my DC Monitoring system. However FAULT and OVRFLW pin are always go low as the chip startup. That mean voltage between AIN+ and AIN- are exceed the fault threshold. But Even if all AIN+- pins are leave floating. FAULT and OVRFLW still go low and DRDYOUT never goes low too.

Anyway I can communicate with this chip through SPI and I can read or write any register. That mean the chip still working.
I'm setting XTALEN bit to 1 and leave everything to default.

I'm trying to measure voltage between AIN+ and AIN-. When the chip is not powered. I can measure the voltage as same as the the voltage source (around 0.124 V) but when chip is powered the voltage between AIN+ and AIN- were dropped to 0.034V and I think because of fault protection circuit in the chip. (this happen whatever I set FAULTDIS in configuration register to 1 or 0)

I read all of the data sheet and in page 15 said that

When the analog input voltage changes between the ADC full scale and the fault threshold faster than the latency of the converter, OVRFLW goes low with the FAULT output. OVRFLW remains invalid until a valid clock frequency is available at XIN.

So I think that it must be something wrong with my Crystal or Capacitor Coupling so I change it from 20pF to 18pF and 10pF and I still have no luck.

Here is my schematic



ADC Datasheet - https://datasheets.maximintegrated.com/en/ds/MAX11040K-MAX11060.pdf

[iMo]

What is the absolute voltage at AIN0+ against AGND, and what is the absolute voltage at AIN0- against AGND??

PS: when you leave the inputs disconnected they may float thus you get overflows..

[SerialCreators]

Hi imo,

When AIN- disconnected from GND and no voltage source between all of AIN+ and AIN-.
Voltage between AIN+ and AIN- is 0.000V and voltage between AIN+- and GND is around 0.095-0.500V

[SerialCreators]

Hi,

After a very long debuging I found a mistake that I accidentally reset a config before waiting a DRDYOUT.
It was a tiny mistake that took me a couple of day to debug. And I accidentally found a mistake after I use an oscilloscope to probe CLKOUT and CS pin.

After solving that issue I found another problem that even I wait a DRDYOUT goes to low and read an adc value the adc value still not valid. They swing from -3000 to 2500 even no input connected. When I apply a 12.2V passing through voltage divider and voltage between AIN+ and AIN- should be 0.122V and ADC value should be 1817 (1817 * (4.4/65535) = 0.1219 V.) but the result was randomly from 25000 to -30000.